Expression of zebrafish oxytocin and vasopressin receptors in HEK293 cells. Pictures were taken using a 100x objective lens. Blue: DAPI; Green: GFP; NTC: Non-Template Control.

(a) Potencies (pEC50 values) of zebrafish oxytocin (zOT), zebrafish vasopressin (zVP) and human oxytocin at zebrafish OT (Oxtr and Oxtrl) and VP receptors (Avpr1aa and Avpr1ab). For p-values, see Results section. (b) L-368,899 dose-response curves for Oxtr, Oxtrl, Avpr1aa, Avpr1ab stimulated by zVP. cpm = counts per minute.

Social preference and anxiety-like behaviours in zebrafish. (a) Time spent in zones of the social preference test in zebrafish adults after acclimation, with Zone 1 being closest to the side tank where the stimulus shoal was placed. (b) Distance between adult focal fish and stimulus shoal in the social preference test, during the acclimation period (0–9 minutes) and test period (10–24 minutes) of the social preference test in adults. (c–e) Shoaling parameters during the shoaling test in adults. (f) Distance to bottom over time during the novel tank diving test in adults. (g) Social preference index (SPI) of the social preference test in larvae, during the acclimation (AC) phase and the social cue (SC) phase. All values are means ± standard error of the mean.

Experimental setup for social preference in adult zebrafish. The focal fish was placed in the test tank, and a stimulus shoal was placed in one of the side tanks, while the opposite side tank contained no fish. Visual barriers were placed between tanks and removed after the acclimation period was complete. Zones were designated as Zone 1 (the zone closest to the stimulus shoal) through to Zone 5 (the zone furthest away from the shoal).

Experimental setup for social preference in 3-week-old zebrafish larvae. Social Preference Index (SPI) was calculated as the formula indicates, for the acclimation period and the social cue period separately.